Quick lookup
Roofing materials for common houses (architectural shingles, 6/12 pitch)
Squares for 6/12 pitch (multiplier 1.118), 10% waste included. 3 bundles per square for architectural shingles. Underlayment: 4 sq ft per square. Cost is materials only at typical 2026 pricing.
| House footprint | Roof sq ft | Squares | Bundles | Underlayment rolls | Materials cost |
|---|---|---|---|---|---|
| 24 × 30 ft | 805 | 9 | 27 | 2 | $1,440 |
| 30 × 30 ft (small) | 1,005 | 11 | 33 | 3 | $1,760 |
| 30 × 40 ft (1,200 sq ft) | 1,340 | 15 | 45 | 3 | $2,400 |
| 32 × 48 ft | 1,718 | 19 | 57 | 4 | $3,040 |
| 35 × 50 ft (1,750 sq ft) | 1,955 | 22 | 66 | 5 | $3,520 |
| 40 × 50 ft (2,000 sq ft) | 2,235 | 25 | 75 | 5 | $4,000 |
| 45 × 60 ft (2,700 sq ft) | 3,015 | 33 | 99 | 7 | $5,280 |
| 50 × 70 ft (3,500 sq ft) | 3,910 | 43 | 129 | 9 | $6,880 |
Multiply by 1.5-2x for total installed cost (labor is usually $300-500/square). Steeper roofs use more material — 12/12 pitch multiplies sq ft by 1.414. Tear-off adds $100-200/square.
Quick answer
How many roofing squares do I need?
Roofing is sold in squares: 1 square = 100 square feet of roof surface. Roof contractors talk in squares because shingle bundles are sold this way (3 bundles per square for architectural shingles). The math: roofArea = footprint × pitchFactor, then squares = ⌈roofArea × waste / 100⌉.
Our calculator uses accurate pitch factors and gives you the full materials list: shingles, underlayment, drip edge, ridge cap, and nails. Includes cost estimate.
The math
The formula explained
Footprint
Measure from the ground (top-down view of your house). Length × width of the rectangle the house occupies.
Pitch factor
Pitch is rise/run (rise in inches per 12 inches of run). A 4/12 pitch rises 4 inches per foot. Steeper pitch means more actual surface area than the footprint.
- 2/12 — 1.014x (nearly flat)
- 4/12 — 1.054x (gentle slope)
- 6/12 — 1.118x (most residential roofs)
- 8/12 — 1.202x (steeper)
- 10/12 — 1.302x (steep, hard to walk)
- 12/12 — 1.414x (45 degrees, very steep)
Waste factor
Simple gable roof: 10%. Complex roof with hips, valleys, or dormers: 15-20%. The waste from cutting around valleys and flashing is real.
Bundle count
Architectural (dimensional) shingles: 3 bundles per square. 3-tab: 3 bundles per square. Premium designer: 4-5 per square. Always round up.
Use cases
Common roof sizes
Small house (30' × 25', 6/12 pitch)
9.2 squares with 10% waste. About 27 bundles + 3 underlayment rolls. $1,500-2,000 in materials.
Average house (40' × 30', 6/12)
14.7 squares. 45 bundles + 4 underlayment. $2,200-3,000.
Large house (50' × 35', 6/12)
21.5 squares. 65 bundles + 6 underlayment. $3,200-4,500.
Ranch with steep pitch (40' × 35', 10/12)
20 squares. 60 bundles. Add 15% labor cost for steep roof.
Garage (24' × 24', 4/12)
6.6 squares. 20 bundles. $1,000-1,400.
Complex roof (40' × 30' with hips and dormers)
14.7 sq × 1.15 = 17 squares. 51 bundles. Plan for extra waste.
Choose your shingles
Shingle types and lifespan
- 3-tab asphalt — $80-100/square. 15-20 year lifespan. Cheapest option. Phased out in some markets.
- Architectural (dimensional) — $100-150/square. 25-30 years. The standard for most homes today.
- Premium designer — $200-300/square. 30-50 years. Look like wood shake or slate.
- Metal roofing — $300-700/square. 40-70 years. Highest upfront cost, longest life.
- Cedar shake — $400-700/square. 30 years. Premium aesthetic, fire concerns.
- Slate — $1,000-2,000/square. 75-150 years. Lifetime roof. Heaviest.
Beyond shingles
The full roofing materials list
- Shingles — main covering. 3 bundles per square architectural.
- Underlayment — synthetic or felt. 1 roll covers 4 squares.
- Ice and water shield — first 3 ft up from eaves in cold climates. Code-required in many states.
- Drip edge — metal edging at eaves and rakes. 10 ft pieces.
- Ridge cap shingles — special bundles for the peak. About 33 ft per bundle.
- Flashing — around chimneys, vents, walls.
- Roofing nails — 1.25 inch galvanized. 1 lb per 100 nails. 320 nails per square (architectural).
- Roofing cement — for sealing flashing and nails.
From a roofer
Pro tips
- Check building permits and HOA rules — most areas require permits for full re-roofs.
- Tear off old shingles when possible — overlaying creates wave patterns and shortens new shingle life.
- Replace any rotten plywood you find during tear-off (count on 1-3 sheets even on a healthy roof).
- Use synthetic underlayment over felt — lighter, more durable, won't tear if it rains before you cover it.
- Drip edge first at eaves, then underlayment over it. Drip edge AT THE RAKES goes ON TOP of underlayment.
- Stagger shingle joints (offset) so seams in one row don't align with adjacent rows.
- Always use 6 nails per shingle in high-wind areas (Florida, coastal areas). 4 elsewhere.
- Replace flashing, do not reuse. New galvanized flashing costs $30-50 and prevents leaks for 20 years.
Roofing is dangerous
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Last reviewed: · Methodology based on US building code standards, contractor pricing surveys, and manufacturer specifications.